This invention relates to a bridge for a stringed musical instrument and more particularly to an adjustable bridge for use with a fretted stringed instrument such as a guitar or bass guitar.
In a fretted stringed musical instrument such as a guitar or bass guitar, proper string height adjustment is critical to the operation of the instrument. If the string height is too low, particularly relative to the instrument fingerboard, an undesirable buzz sound will occur when the instrument is played, resulting from spurious contact of the strings with one or more frets; while if the string height is too high, the musician must apply excessive pressure to the strings, making the instrument difficult and uncomfortable to play. Such instruments will normally be factory adjusted for proper string height; however changes in temperature or humidity may effect subtle changes in the body or neck of the instrument necessitating an adjustment in the height of one or more strings. Changing the string gauge or type of string used on the instrument may also require a change in string height, or a musician may decide that changes in string height are necessary or desirable for other reasons.
In addition to changing string height, it may also be necessary, as a result of the factors indicated above or otherwise, to change the intonation of one or more strings of the instrument by adjusting the point on the string at which the string contacts the bridge saddle and the musician may also wish to vary the spacing between strings.
Prior art bridges have provided various means for performing one or more of the adjustments indicated above. However, in performing the string height adjustment, these bridges have generally relied on one of two methods. Perhaps the most common approach is to mount the bridge or bridge saddle assembly on the instrument body by use of a screw at either end with a thumb nut or similar element being provided on each screw to permit raising or lowering of the entire bridge. This approach has a number of drawbacks. First, this technique is only operative for raising or lowering all of the strings and it not adapted to individually adjust the height of each string. Second, it is sometimes difficult to uniformly adjust the screws resulting in uneven string height and other potential problems. But perhaps the most serious deficiency is the fact that the only contact between the bridge and the instrument body is through the two screws. This significantly weakens the ability of the instrument to transmit string vibrations to the instrument body and therefore adversely effects the sustain characteristics of the instrument. Ideally, there should be solid metal contact all the way from the bridge saddle to the instrument body.
The second approach to string height adjustment overcomes some of the problems indicated above by providing a screw adjustment for each individual bridge saddle. However, physical contact between the bridge saddle assembly and the bridge base and thus the instrument body is still made only through a single point at the end of a screw resulting in little mass at the adjustment point. As with the previous approach, this adversely effects the sustain characteristics of the instrument.